Recently, organic pigments have been widely used in display materials, optical recording media, materials for inkjetting, and the like. When a pigment is used in a coating process or an inkjet process, a pigment having high solubility in a solvent in addition to having a high molar absorption coefficient is required in order to improve coloring efficiency.
As a new image display technology, displays using an electrowetting method (EWD) have recently been receiving attention (see, for example, Nature (London), 425, 383 (2003)). The display has an image display mode that is operated by disposing, on a substrate, plural pixels filled with two phases, which are a hydrophilic medium and an oil colored ink, controlling the affinity at the interface of the hydrophilic medium/oil colored ink by ON/OFF control of voltage application to each pixel, and developing/modifying the oil colored ink on the substrate. Pigments used in a display manufactured by the electrowetting method are required to have high solubility in a hydrocarbon-based solvent.
Various pigments are known, and among these, an azomethine pigment has been widely used as a dye for photography (see, for example, Journal of the American Chemical Society, Volume 97, page 2764, 1975).
Further, pyrrolo triazole-based and pyrazolo triazole-based azomethine pigments, and the like having excellent absorption properties or toughness have been proposed as an azomethine pigment (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2003-96327 and JP-A No. 2002-256164).